Sheet feeding apparatus



Sept. 4, 1956 G. w. TEBBS SHEET FEEDING APPARATUS 6 Sheets-Sheet 1 Filed April l3, 1953 \NVENTOR m&

. RX/QQ is Q @R QM cw Sept. 4, 1956 w. TEBBs SHEET FEEDING APPARATUS a Sheefs-Sheet 2 Filed April 15, 1953 INVENTOR ATTORNEY Sept. 4, 1956 e. w. TEBBS SHEET FEEDING APPARATUS 6 Sheets-Sheet 4 Filed April 15, 1953 2 "w 2 S w l 0 u. ,m 1.: .a. a,

90% a. 6m ATTORNEY Sept. 4, 1956 G. w. TEBBS SHEET FEEDING APPARATUS 6 Sheets-Sheet 5 Filed April 13, 1953 lNVENTOR ATTORNEY Sept. 4, 1956 G. w. TEBBS SHEET FEEDING APPARATUS 6 Sheets-Sheet; 6

Filed April 15, 1955 5. INVENTOIiT W M AM BY U 00%, Q. ATTORNEY Fig. l is a perspective view of a sheet feeder constructed in accordance with the present invention, said view being to some extent diagrammatic, and omitting certain of the feeder parts for purposes of clearer illustration;

Fig. 2 is a side elevational view of the upper portion of said sheet feeder looking at the gear side thereof or from the right of Fig. 1;

Fig. 3 is a side elevational view of the upper portion of said sheet feeder looking at the feed side thereof or from the left of Fig. 1;

Fig. 4 is a detail side elevational view of a worm and worm gear drive for lowering and raising the sheet sepaating mechanism, and including pawl and ratchet mechanism and control means for operating said drive to effect lowering of said sheet separating mechanism;

Fig. 5 is a top plan view, partly in section, of the structure shown in Fig. 4, with the control means omitted for purposes of clearer illustration;

Fig. 6 is a top plan view, partly in section, of the sheet separating unit located at the feed or left-hand side of the feeder;

Fig. 7 is a vertical transverse sectional view substantially on the line 77 of Fig. 6;

Fig. 8 is an end elevational view of said sheet separating unit looking from the right of Fig. 6;

Fig. 9 is a vertical longitudinal sectional view substantially on the line 99 of Fig. 6;

Fig. 10 is a side elevational view showing the upper portion of the mechanical gripper chain conveyor unit located at the gear or right-hand side of the feeder, said view being taken from the feed or left-hand side of the machine;

Fig. 11 is a view similar to Fig. 10, but showing the lower portion of said mechanical gripper chain conveyor unit;

Fig. 12 is a horizontal sectional View of the line 1PM of Fig. 10;

Fig. 13 is a horizontal sectional view on the line .1313 of Fig. 10;

Fig. 14 is a horizontal sectional view on the line 14-14 of Fig. 11;

Fig. 15 is a side elevational view of one of the sheet gripping devices showing the same in the position it oecupies as it travels toward the top of the pile of sheets;

Fig. 16 is a view similar to Fig. 15, but showing the sheet gripping device substantially in the position it occupies as it approaches the upper end of its course with a sheet gripped thereby;

Fig. 17 is a diagrammatic side elevational view showing one set of sheet gripping devices and the operation of said devices at various positions along its course;

Fig. 18 is a detail side elevational view showing the rear portion of an endless tape conveyor at the top of the feeder;

Fig. 19 is a side elevational view showing diagrammatically the manner in which the sheets are separated and forwarded in lapped relation from the pile;

Fig. 20 is a fragmentary detail perspective view of a modified form of mechanism for driving and timing the sheet separating mechanism.

Figs. 21 and 22 are side elevation and top plan views, respectively, of a modification of the form of driving mechanism shown in Fig. 20, Fig. 22 being partly in section and having portion of certain of the parts broken away for purposes of clearer illustration; and

Fig. 23 is a rear elevational view of another modified form of mechanism for driving and timing the sheet separating mechanism.

Referring now to the drawings and particularly to Fig. 1 thereof, there is shown, by way of example, one form of sheet feeder constructed in accordance with the present invention, which is adapted for feeding sheets of paper, card stock, or the like, from the top of a stationary pile 20 thereof to a tape conveyor 21 in a manner such that the sheets are conveyed in the form of a stream of underlapped sheets to a printing or other ma chine for operating on the individual sheets of said stream.

The machine comprises a frame composed of four uprights 22, 23, 24 and 25 secured to pairs of top and bottom brackets 26 and 27, respectively, said top brackets being interconnected by crossbars 28, 29 and 3t and said bottom brackets being interconnected by a crossbar 31. Guided on the uprights 22 to 25 for vertical movement downwardly and upwardly is a carriage comprising guide blocks and 36 interconnected by tubular crossbars 37 and Supported on the carriage for vertical move ment therewith are two similar sheet separating mechanisms 39, one only being shown in Fig. 1, which are slidably mounted on the crossbars 37, 38 for adjustment toward and away from each other in accordance with the various sizes of sheets being handled and to locate said mechanisms at the desired points with reference to their operation upon front corner portions of the sheets at the top of the stationary pile 20. Also supported on the carriage for vertical movement therewith are two similar cam units 40 and 41 which are also slidably mounted on and adjustable to various positions along the crossbars 37, 38 of said carriage.

Disposed between the sheet separating mechanisms 39 and forwardly of and in close proximity to the stationary pile of sheets 20 is an upright conveyor which, in the illustrated embodiment, is in the form of a plurality of transversely spaced endless chain gripper type units, two only being shown and indicated at 45 and 46 (Fig. 1). These units 45, 46 each have elements thereof, to be hereinafter described, slidably mounted on the crossbars 29 and 31 for adjustment of said units independently toward and away from each other by means of pinions 47 and 48 which have meshing engagement with rack teeth formed on said crossbars. The pinions 47, 48 for each unit 45, 46 are secured to the opposite ends of an upright shaft 44 which is journalled in a suitable manner on the respective unit and is rotated by means of a handwheel 49 secured to said shaft. The cam units 40, 41 are preferably arranged for lateral adjustment in unison with the chain gripper units 45, 46, and for this purpose the cam unit 40 has portions thereof disposed at opposite sides of an upright portion of its associated chain gripper unit 45, and the cam unit 41 has similar portions disposed at opposite sides of an upright portion of its associated chain gripper unit 46.

The drive for the feeder is taken from a suitable source of power (not shown) suitably connected to a main drive shaft 43 (Figs. 2 and 3) which extends transversely of the feeder and is journalled in suitable hearings in the upper side frame brackets 26. Fixed on the shaft 43 is a spur gear 50 (Figs. 1 and 2) which drives a similar gear 51 through a similar intermediate gear 52. The intermediate gear 52 is journalled in a suitable manner on the adjacent upper side frame bracket 26, and the driven gear 51 is fixed on and drives a shaft 60 which extends transversely of the feeder and is journalled in suitable bearings in the upper side frame brackets 26. The gears 50 and 51 are so proportioned that the shaft 60 will make one complete revolution for each cycle of operation of the feeder.

Fixed on the single revolution shaft 69 at the gear side end thereof and disposed exteriorly of the adjacent upper side frame bracket 26 is a sprocket 53 (Fig. 2) around a portion of which passes an endless chain 57. From the sprocket 53 the chain 57 passes downwardly over and around an idler sprocket 54 to the bottom of the feeder and then passes rearwardly under and around an idler sprocket or guide disk 55 (Fig. 1). From the sprocket or disk 55 the chain 57 passes upwardly then forwardly over and around an idler sprocket 67, then upwardly around and in front of a drive sprocket 65, then upwardly under and around a similar idler sprocket 67', and then upwardly and forwardly over and around another idler sprocket 56 to the driving sprocket 53.

The idler sprockets 54 and 56 are journalled onstub shafts 58 and 59, respectively, anchored in the adjacent upper side frame bracket 26, the stub shaft 59 being arranged for relative vertical adjustment whereby any slack in the chain 57 maybe taken up and the desired degree of tightness of said chain may be obtained. The idler sprocket or disk 55 is journalled'on a stub shaft 6L anchored in the adjacent lower side frame bracket 27, and the idler sprockets 67 and 67 which serve to hold the chain 57 in meshing. engagement with the sprocket 65 are journalle'd. on stub shafts 62 and 63, respectively, which are anchored in the guide block 35 of the vertically movable separator carriage. The drive sprocket 65 is fixed on the outwardly projecting gear side-end of a shaft 66 which extends transversely of the feeder and is journalled in suitable bearings provided in the guide blocks 35 and. 36 of. the vertically movable separator carriage. The sprockets 53 and 65" are of the same diameter and hence shaft 66, like shaft 69, is driven tomake one complete revolution for each cycle of operation of the feeder. The shaft 60 and sprocket 53 thereon are driven continuously in a clockwise direction, as viewed in Fig. 2, and hence the chain 57 will also be driven continuously by said sprocket and such that the rear vertically extending active reach thereof which meshes with and drives the sprocket 65 travels in an upward direction. Under these conditions, the shaft 66 which is carried by and vertically movable with the separator carriage will be driven by the chain 57 and sprocket 65 continuously and ina direction opposite to the direction of rotation of the shaft 60; The shaft 66 is utilized to drive the sheet separating mechanisms 39 and to operate other parts of the feeder, as will be hereinafter described.

The separator carriage is shown in broken lines in Figs. 2 and 3 in the extreme uppermost position which it occupies when a pile of sheets of maximum capacity is loaded in sheet feeding position, and substantially when the sheet separating mechanisms 39 operate initially on the top of a pile 20 of maximum height. The separator carriage is shown in Fig. 1 in a lowered position after a major portion of the sheets have been fed from the top of the stationary pile 2i and said pile has depleted an appreciable amount. With a pile of sheets 20 loaded in feeding position, the separator carriage is lowered to properly locate the sheet separating mechanisms 39 with respect to the top of said pile for performance of the sheet separating operations thereon. As the sheets are separated and fed successively from the top of the stationary pile 26 during the normal operation of the feeder and said pile is consumed and decreases in height, "the separator carriage and the sheet separating mech nisms 39 thereon are progressively lowered with the change in the level of the top of the pile to enable continued separation and feeding of sheets from said pile. it is thus to be noted that by virtue of the described arrangement and operation of the chain 57 and its driving connection with the sprocket 65 on shaft 66, rotation will be imparted to said shaft in all vertical positions that the separator carriage and sheet separating mechanisms 39 may occupy during normal operation of the feeder and feeding of sheets from the top of the stationcry pile 20. It is also important to note that the sprocket v on the shaft 66 will roll along the upwardly traveling reach of the chain 57 upon vertical movement or". the separator carriage. Accordingly, when the carriage and the sheet separating mechanisms 39 thereon arep rogressively lowered during the normal operation of the feeder, the shaft 66, due to the rolling action of the sprocket 65 along the chain 57, will be rotated in the direction of its normal rotation, thus progressively advancing the cyclic timing of the operations of the sheet separating mechanisms. Each time the separator carriage is lowcred, the degree of relative advance rotation of the shaft 66 is commensurate tothe extent of downward movement. of said carriage sothat when the latter has been lowered a distance equal to the spacing between the sheet gripping devices on the chain units 45, 46 of the upright conveyor, the shaft 66 will be advanced one complete revolution. To achieve this result, the sprocket 65 is so chosen that the circumference thereof on the pitch line is equal to the distance between the sheet gripping devices. In this. manner, the timing relationship of the operations of the sheet separating mechanisms 39 with the operation and cycle of movement. of the sheet gripping devices of the upright conveyor is maintained as said mechanisms descend so that separation of successive sheets at the proper time and proper engagement of said sheets by said gripping devices at the-progressively changing level of the top of the pile is always assured. Similarly, when the separator carriage and the sheet separat ing mechanisms 39 thereon are: raised, the shaft 66, due to the rolling action. of the sprocket 65 along. the chain 57, will be given a backward rotation, i. e., in the direction reversely to its normal rotation, thus retarding the cyclic timing of the operations. of the sheet separating mechanisms relative to the operation and cycle of movement of the sheet gripping devices.

As previously stated, the separator carriage and the sheet. separating mechanisms 39 thereon are lowered. as sheets are fed from the top of the stationary pile 20, and in order to maintain said mechanisms at the proper level with respect to the top of the diminishing; pile for continued separation and feeding of sheets from said pile, this lowering of the separator carriage is effected at suitable intervals under the control of the pile by mechanism constructed, mounted, operated, and controlled as follows. Extending transverselytof the feeder and carried by the separator carriage. for vertical movement therewith is a shaft 95 (Fig. 1) which is rotatably mounted within the tubular crossbar 38 and projects beyond opposite ends of said crossbar. The feed side end of the shaft 95 also projects through and is further journailed in a suitable bearing provided in a bracket 92 (Figs. 1, 4 and 5) which. is secured to the outer surface of the guide block 36 of the separator carriagea Fixed on the shaft 95 and disposed exteriorly of the guide blocks 35 and 36 are spur pinions 96 and 97 which mesh with rack teeth 98 and 99-, respectively, formed on and along a major portion of the rear edges of the uprights 23 and 25, respectively, said guide bloc-ks being suitably recessed to receive said pinions. Rotation of the shaft 95 in opposite directions will thus impart lowering and raising movements to the separator carriage. and the sheet separating mechanisms 39 thereon;

The single revolution shaft 66 on: the separator carriage also projects through and beyond the bracket 92 on said carriage (Figs. 1, 4 and 5), and fi-xed on the outwardly projecting end of said shaft is a cam 84 which engages a roller 83 journalled on a cam strap 81 engaged over the shaft 66. The cam strap 81 extends between the furcations of a bifurcated pawl carrier 86 and ispivotally connected as at 8-5 to said pawl carrier. The roller 83 is biased toward the cam 84 by a coil extension spring 91 having. one end thereof connected to the pawl carrier 86 and the opposite end connected to the bracket 92. The pawl carrier 86 is disposed between vertically spaced bearing portions 82 and 82 of the bracket 92 and is pivotally mounted for oscillating movement on: a vertically extending shaft 87 which passes through and is journalled in suitable hearings in said portions. The shaft 87 is: held against axial movement ina suitable manner and is journalled at opposite ends, thereof in suitable hearings in brackets 88 and 88 which are secured to the adjacent upper and lower side frame brackets 26 and 27, respectivelyi Pivoted at on the pawl carrier 86 is a spring pressed pawl 89 adapted to continuously and yieldingly engage a ratchet 90 which is disposed between the furcations of said pawl carrier. The ratchet 90 is mounted on the: shaft 87 for sliding'movement therealong and is drivably connected to said shaft as by a key and keyway connection to enable movement thereof along the shaft with the separator carriage and to impart rotation to said shaft in all axial positions thereof on the shaft.

Disposed between the pawl carrier 86 and the bearing portion 82 on the bracket 92 is a worm 93 (Fig. 4) which is mounted on the shaft 87 for relative sliding movement and is drivably connected, as by a key and keyway connection, to said shaft for rotation by the latter in all vertical positions of the separator carriage. This worm 93 meshes with and drives a worm gear 94 which is disposed exteriorly of the bracket 92 and is fixed on the outwardly projecting feed side end of the shaft 95. Through oscillation of the pawl carrier 86 by the cam 84 and spring 91, and engagement of the pawl 89 with the ratchet 90, the shaft 95 and pinions )6, 97 thereon are thus intermittently rotated in a clockwise direction, as viewed in Fig. 1, through the described worm and worm gear gearing between said shaft and the shaft 87, thereby imparting step by step downward movement to the separator carriage and the sheet separating mechanisms 39 thereon, including the shaft 66, cam strap 81, cam 84, pawl carrier 86, ratchet 90, bracket 92, Worm 93, worm gear 94 and shaft 95, as well as the cam units 40 and 41. The drive between the worm 93 and the worm wheel 94 is self-locking.

During the normal operation of the feeder and as sheets are separated and fed from the top of the stationary pile 20, this step by step downward movement of the separator carriage and the sheet separating mechanisms 39 and other described parts thereon is controlled by a pile height determining feeler or finger 70 (Fig. l) which is carried by said separator carriage and is preferably located to project over and engage the top of the pile of sheets at the front edge and substantially in the center thereof. The feeder 70 is adjustably secured to a rock shaft 71 (Figs. 1 and 4) which extends transversely of the feeder and is journalled in suitable bearings in the guide blocks 35 and 36 of the separator carriage. The feed side end of the shaft 71 also projects through and beyond a suitable bearing in the bracket 92. Fixed on the outwardly projecting feed side end of the shaft 71 is an arm 73 having journalled thereon a roller 74 which engages a cam 72 (Figs. 1 and that is fixed on the single revolution shaft 66 and serves to hold the cam strap 81 in operating position with respect to the cam 84. The roller 74 is biased toward the cam 72 by a coil extension spring 69 having one end thereof connected to the arm 73 and the opposite end connected to the bracket 92. Once during each cycle of operation of the feeder the shaft 71 will thus be rocked in one direction by the cam 72 to raise the feeler 70 out of engagement with and clear of the front edge of the pile of sheets 20, and in the opposite direction by the spring 69 to lower the feeler 70 into engagement with the top of said pile. The operations of the feeler 70 are so timed that just prior to and during separation of the front edge portion of the top sheet from the pile 20 said feeler is moved upwardly and forwardly from and clear of said pile and held in its actuated position until the separated sheet is transferred to and taken by the upwardly moving chain gripper units 45, 46, and is then returned under the separated sheet into engagement with the top of the pile and held in this position until just prior to separation of the front edge portion of the next or underlying sheet on said pile.

Fixed on the feeler shaft 71 or formed integrally with the arm 73 is another arm 75 (Figs. 1 and 4) having threaded therein an adjustable tappet 76 which is adapted, under certain conditions, to engage one arm 77 of a double-armed latch lever which is pivotally mounted on the feeler shaft 71. The other arm of the latch lever is indicated at 78 and has secured thereto a hardened steel latch plate 79 which is adapted to Cir normally engage the bevelled forward end of a companion hardened steel plate 80 secured to the upper surface of the cam strap 81. Engagement of latch plate 79 with plate 80 holds the cam strap 81 against return movement by the spring 91, thus preventing the roller 83 from following the low part of the cam 84 and operation of the pawl carrier 86 to engage the pawl 89 with the next tooth of the ratchet 99. The plate 80 is so located on the cam strap 81 that when the roller 83 is engaged by the high part of the cam 84, said plate is moved clear of the latch plate 79 so as to free the latter for pivotal movement out of engagement with the plate 80 and out of the path of return movement of said cam strap.

When the shaft 71 is rocked in the proper direction by spring 69 to engage the feeler 70 with the top of the stationary pile of sheets 20, the arm with the tappet 76 thereon is also rocked in the same direction toward the latch lever arm 77. As long as the sheet separating mechanisms 39 are disposed at the proper level with respect to the top of the pile of sheets 20, the feeler 70 will be prevented by the pile from moving downwardly a distance sufiicient to enable the tappet 76 on arm 75 to engage the latch lever arm 77. The separator carriage and the sheet separating mechanisms 39 thereon will thus remain stationary because the pawl carrier 86, through engagement of the latch plate 79 with the cam strap 81, will be held in its power stroke position and prevented from returning to enable the pawl 89 to engage the next tooth of the ratchet 90.

When the height of the pile of sheets 20 decreases sufficiently through removal of sheets from the top thereof so that lowering of the separator carriage and the sheet separating mechanisms 39 thereon is necessary, the tappet 76 on arm 75, through increased downward movement of the feeler 70, is enabled to engage the latch lever arm 77 and swing the latch lever sufficiently to disengage the latch plate 79 from the cam strap 81, thus rendering the pawl and ratchet mechanism operative to lower the separator carriage and the sheet separating mechanisms, as well as the cam units 40 and 41 on said carriage. When the feeler 70 is subsequently raised out of engagement with the top of the pile of sheets 20, the tappet 76 on arm 75 is swung away from the latch lever arm 77, whereupon the latch lever is released and allowed to return by gravity, aided by a light spring if necessary, to its original position so that the latch plate 79 is again positioned in the path of return movement of the cam strap 81, thus rendering the pawl and ratchet mechanism inoperative to further lower the separator carriage and the sheet separating mechanisms thereon. Upon each operation of the pawl and ratchet mechanism, the sheet separating mechanisms 39 will be lowered an extent sufficient to enable separation and feeding of a number of sheets from the top of the pile 20 before lowering of said sheet separating mechanism is again necessary.

The operating level of the sheet separating mechanisms 39 with respect to the top of the stationary pile of sheets 20 may be varied as desired to accommodate different stock conditions, and this is accomplished by rotating the adjustable tappet 76 which may be effected while the feeder is in operation. Adjustment of the tappet 76 toward the latch lever arm 77 will cause said tappet to engage said arm sooner with the result that the normal level of the sheet separating mechanisms will be disposed in a lower plane with respect to the top of the pile of sheets. Similarly, when the tappet 76 is adjusted away from the latch lever arm 77, said tappet is caused to engage said arm later with the result that the normal level of the sheet separating mechanisms will be disposed in a higher plane with respect to the top of the pile of sheets, If it is desired to lower the separator carriage and the sheet separating mechanisms thereon once during each cycle of operation of the feeder, as when handling thick sheets, such as cardboard, this may be accomplished by adjusting the tappet 76 toward the latch leve arm 77 to a position such that it engages said arm and actuates the latch lever each time the feeler 70 is moved toward and into engagement with the .top of the pile of sheets 20. In this case, the cam strap 81 will be released and the pawl and ratchet mechanism will be operated once during each cycle of operation of the feeder to lower the separator carriage and the sheet separating mechanisms thereon an appropriate amount as the sheets are fed one after another from the top of the pile 20.

The described worm and worm gear drive 93, 94 serves as an automatic brake and thus holds the separator carriage in all elevated positions and against sliding downward movement under the weight thereof. vIn lieu of the worm and worm gear drive, the separator carriage may, if desired, be attached to and suspended by suitable cables which are provided with suitable weights which tend to raise said carriage. In this case, a suitable self-locking type of pawi and ratchet mechanism is provided to check the separator carriage against upward movement by the weights, and to drive said carriage downwardly, said pawl and ratchet mechanism being drivably connected with the shaft 95 and being effective under the control of the feeler 70 in the manner above described. Also, if desired, the feeler 70 may be in the form of blast nozzle connected with a source of compressed air so as to direct air under pressure rearwardly between each separated sheet and the pile and thereby completely separate and float said sheet while it is being removed or fed from the pile.

The separator carriage and the sheet separating mechanisms 39 and cam units 40 and 41 thereon may be manually raised and lowered to desired positions, and for this purpose the shaft 87 has fixed on the upper end thereof a bevel pinion 100 (Figs. 1 and 3) which meshes with a bevel gear 101 that is journalled on a short transversely extending shaft 102 fixed at the inner end thereof in the bracket 88. Rotatably mounted on the outer end of the shaft 102 is a handwheel 103 which is also axially slidable on said shaft so as to permit it to be brought into clutching engagement with the hub, of the bevel gear 101 to rotate the latter in either direction and thereby impart like rotation to the shaft 8 7'through the bevel pinion 100 to raise and lower the separator carriage. To free the ratchet 90 from the power operated mechanism when the handwheel 103 is employed to manually raise or lower the separator carriage, an arcuate pawl releasing arm 106 (Figs. 1, 4 and 5) is slidably fitted over a vertically extending square bar 105. and is held in operating relation to the pawl 89 between tubular extensions of the bearing portions 82, 82' of the bracket 92 on the separator carriage. The bar 105; passes through and is rotatable in the tubular extensions of the bracket 92, and is provided at the opposite ends thereof with reduced annular portions which are journalled in suitable bearings in the brackets 88 and 88' (Figs. 1 and 3). Fixed on the upper end of the bar 105, is an arm 104 which extends forwardly from said bar between the bevel gear 101 and the handwheel 103 and has journalled thereon a roller 107. The arm 104 is biased in the direction of the handwheel 103 by a coil extension spring 109 having one end thereof connected to said, arm and the opposite end connected to the adjacent upper side frame bracket 26.

As the handwheel 103 is moved axially into clutching engagement With the bevel gear 101,, the hub of said, handwheel engages the roller 107 on arm 104 and rocks said arm toward the feeder frame, thus rocking the square bar 105 in the same direction and causing the pawl releasing arm 106 on said bar to engage a tailpiece 108 of the pawl 89. (Fig. 5) and swing said pawl out of engagement with and clear of the ratchet 90. The shaft 87 may then be rotated in opposite directions upon clutching engagement of the handwheel 103 with the bevel gear 101 and rotation of said handwheel to. raise or lower the epa t r carr ag manual raising. and.

10 lowering of the separator carriage may be efiected while the feeder is in operation and. without disturbing the timing relationship of the various mechanisms. When the handwheel 103 is moved out of clutching engagement with the bevel gear 101, the arm 104 is released and said arm, the bar 105, and the pawl releasing arm 106 are then returned to their original positions by the contractmg action of the spring 109, thus releasing the pawl 89 to again engage the ratchet 90.

The sheet separating mechanisms 39 are arranged for operation at opposite sides and. near the front edge of the pile of sheets 20, and act to preliminarily separate the front opposite corner portions of the top sheet from said pile and then to simultaneously stretch and lift the entire front edge portion of said sheet to a predetermined positron above the pile for accurate transfer to and engagement by the gripping devices on the chain gripper units and 46. The sheet separating mechanisms 39 are constructed one right-hand and the other left-hand, the righthand mechanism being diagrammatically shown in Fig. l and disposed outwardly of the chain gripper unit 45, and the left-hand mechanism being shown in detail in Figs. 6 to 9 and occupying a corresponding position outwardly of the chain gripper unit 46, and since the construction of said mechanisms are otherwise identical, a description of one will suffice for both.

Each sheet separating mechanism 39 comprises a casing 110 slidably mounted on the cross bars 37, 38 of the separator carriage and provided with a guiding member 111 engaged with the crossbar 37, and with clamping members 112 engaged with the crossbar 38 for securing said casing in various positions of adjustment along said Crossbars. Each casing 110 is suitably constructed to provide suitable clearance openings for the shafts 66 and 71 to extend therethrough. Disposed within each casing 110 is a bevel gear 115 which is keyed to the single revolution shaft 66 for rotation thereby and for sliding movement along said shaft with said casing. This bevel gear 115 meshes with and drives a bevel gear'114 which is fixed on a short horizontal cam shaft 113 journalled in suitable hearings in the casing 110. The bevel gears 114 and 115 are of the same diameter and, hence, the cam shaft 113 of each separator mechanism will be driven to make one complete revolution for each cycle of operation of fihe'feeder. The cam shafts 113 of the separator mechanisms are driven by the gears 114, 115 so that they rotate in opposite directions, i. e., toward each other and the pile of sheets 20, as indicated by the arrow in Figure 7.

Keyed to the shaft 113 of each separator mechanism 39 within the casing 110 is a cam 118 which engages a roller 129 journalled on one arm 128 of a bell crank having another arm 125 projecting transversely of said casing toward the pile of sheets 20. The bell crank 125, 128 is, pivotally mounted on a rock shaft 126 extending longitudinally of the feeder and parallel to the shaft 113 and the adjacent side of the pile 20 and journalled in bearings in the casing 110. Journalled as at 121 on the inner free end of the bell crank arm 125 is a combing wheel 127 having secured thereto a sprocket 124 around which passes a chain 123 which also passes around a sprocket 122 secured to one end of a sleeve 116. This sleeve 116 is journalled on the shaft 126 and has secured to the other end thereof a spur pinion which meshes with a spur ear 117 that is secured to the cam 118. The combing wheels 127 are, rotated in the direction of the arrows indicated in Figs. 1 and 7 through the described driving connections for said wheels with the cam shafts 113.

Each bell crank arm has pivotally connected therewith at 143 (Fig. 7) the upper end of a vertically disposed spring-pressed rod 144 the lower end of which extends through a suitable clearance opening in an arm 145 which is. pivotallymounted at 146 on the casing 110. The arm 145 rests. on an adjusting nut 147 which 1 1 is threaded on the lower end of a stem 148 that projects through a suitable elongated opening in said arm and is secured at the upper end thereof in the casing 110. The coil compression spring for rod 144 is indicated at 149 and mounted thereon between the head of said rod and the arm 145. Each bell crank arm 125 has also connected therewith at 143 one end of a coil extension spring 149 the opposite end of which is connected at 149" to the casing 110. This spring 149' operates to counter-' balance the weight of the bell crank 125, 128 and parts carried thereby so that downward movement of the combing wheel 127 is effected solely by the spring-pressed rod 144, and the degree of pressure of said combing wheel on the pile is solely under the control of the spring 149.

The combing wheels 127 are thus spring operated toward and into frictional engagement with the top of the pile of sheets 20, and cam operated away from and out of engagement with said pile, and the pressure of the springs 149 and resulting pressure of the combing wheels on the pile may be adjusted by rotating the nuts 147 and thereby vertically adjusting the arms 145. Once during each cycle of operation of the feeder, and at the proper time, the combing wheels 127 are lowered on to the top of the pile of sheets 20 and effect a preliminary separation of the top sheet by moving the front opposite corner portions of said sheet inwardly towards each other where by small buckles or humps are formed in the sheet adjacent said corners. In order to confine this preliminary separation of the top sheet by the combing wheels 127 to the opposite corner portions of said sheet, two presser fingers 142 (Fig. 1) are lowered into engagement with the top of the pile a short distance, inwardly from said combing wheels. These presser fingers 142 are rocked by the feeler shaft 71 into and out of engagement with the top of the pile of sheets 20 in unison with the feeler 70, and are yieldingly mounted on said shaft so as not to affect the pile height sensing operation of said feeler.

After preliminary separation of the top sheet has been effected at its front opposite corners by the combing wheels 127, the sheet is engaged at its buckled corner portions by two suction devices which operate to lift said sheet from the pile and stretch the same in a direction transversely to the feeding direction. This stretching of each sheet straightens and raises its entire front edge portion for accurate engagement at spaced points along said edge by the gripping devices on the chain gripper units and 46. The suction sheet lifting and stretching devices form a part of the sheet separating mechanisms 39 and are similar, and each of said devices is constructed, mounted and operated as follows.

Each cam shaft 113 has fixed thereon a cam 119 which engages a roller 131 journalled on an arm 139 which is secured to the rock shaft 126. Fixed on the projecting rear end of the rock shaft 126 is a lever 133 which projects from said shaft inwardly towards the pile of sheets 26. Fitted in the lever 133 for sliding movement lengthwise thereof is a rod 134 which is held against rotation relative to said lever by a square block 135 secured to said rod and disposed between spaced inner and outer portions of the lever relatively close to a guiding surface 136 of said lever. The rod 134 projects beyond the inner end of the lever 133 and has secured to its inner end a clamp 132. Secured in the clamp 132 is a tubular fitting 139 which forms a part of a suction sheet gripping device which is preferably, but not necessarily of a well-known type comprising a cylinder 141 communicating with said fitting, a hollow piston stem 141 in and communicating with said cylinder and projecting downwardly beyond the lower end of the cylinder, and a rubber suction cup 141) fixed on the fewer end or" said stem and communicating with the latter and said cylinder. Stern 141' and cup 140 are actuated downwardly by a spring (not shown), and are actuated upwardly by vacuum when said cup has gripped and is sealed by a sheet. The rod 134 and the suction sheet gripping device carried thereby are yieldingly urged inwardly towards the pile of sheets 20 by a coil compression spring 134' surrounding said rod and having one end thereof engaging against the clamp 132 and the opposite end engaging against the inner end of the lever 133, said inward movement being limited through engagement of the block 135 with the inner portion of the lever 133. Engagement of the blocks 135 with the inner portions of the levers 133 serves to properly locate the suction sheet gripping devices for operation on the separated corner portions of the top sheet of the pile 20.

Each suction sheet gripping device is yieldingly urged downwardly into engagement with the top of the pile of sheets 20 by a coil extension spring 133' having one end thereof connected to the lever 133 outwardly of the pivotal axis 126, and the opposite end connected to a block or shelf 119 secured to or formed integrally with the casing 110, said spring also serving to yieldingly urge the roller 131 toward the cam 119. The levers 133 are thus raised by the cams 119 and lowered by the springs 133'. thereby raising and lowering the suction sheet gripping devices at intervals such that following preliminary separation of the opposite front corner portions of the top sheet by the combing wheels 127, the suction cups 149 will, upon creation of vacuum in the cylinders 141, grip the inwardly combed humped portions of: said sheet and further separate them through retraction of the stems 141 into said cylinders. T hereupon the suction devices are swung upwardly and outwardly away from each other toward the sides of the pile of sheets 2% to lift the sheet at its front edge, and at the same time transversely stretch the entire front edge portion of said sheet in a manner to be presently described. The cams 118 and 119 are so chosen that when the respective rollers 129 and 131 are engaged with the high parts of said cams, the combing wheels 127 and the suction sheet gripping devices are swung upwardly and outwardly beyond the vertical projection of the sides of the pile of sheets 20. as shown in broken lines in Figs. 7 and 8, so as to clear the separated sheet and not interfere with the removal thereof in an upward direction from said pile. The timing relationship of the combing wheels 127 and the suction sheet gripping devices is such that the lowering and raising operations of said combing wheels precedes the lowering and raising operations of said suction devices and that the combing wheels are raised substantially the instant the sheet is gripped by the suction devices.

Stretching of the entire front edge portion of the separated top sheet by the suction devices is effected through outward movements of said suction devices away from each other which occurs as the suction devices move upwardly and while said sheet is being lifted thereby a short distance away from the top of the pile 25 For this purpose, each block 135 has journalled thereon a roller 137 (Figs. 6 and 8) adapted to engage an inclined cam arm 138 which is pivotally mounted at 138 on the casing 110. The cam arm 138 has threaded therein outwardly of the pivot 138 an adjustable abutment screw 137' adapted to engage the upper surface of the shelf or block and thereby prevent upward swinging movement of said arm about its pivot 138. The cam arm 138 may be adjusted on its pivot 138' to various operating positions with respect to the roller 137 by rotating the abutment screw 137 in opposite directions.

The cam arms 138 continuously engage the rollers 13'] and are so formed and located that the lower edges thereof engaged by said rollers are disposed inside the arc of swinging movement of the rollers about the axes 126. Accordingly, when the suction devices are moved downwardly as hereinbefore described, the rollers 137 will move downwardly along the cam arms 3- 3 and permit the rods 134 to be axially extended by the expanding action of the springs 134 until the blocks on said 13 rods engage the inner portions of the, levers 133 and the suction devices are thereby properly positioned for gripping of. the inwardly combed humped corner portions:

through upward movement thereof and engagement of the rollers 137 with the cam arms 138, will be forced by said cam arms outwardly away from each other relative to the levers 133, thereby stretching the entire front edge portion of the sheet substantially through equal outward movements of the suction devices, to an extent depending. on the slack or sag in the sheen/the cam arms 138, being: so adjusted to; effect this stretching, operation duringlifting of the sheet, a shortdistance from the top. of the pile 20 and without causing the suction devices to tear or slip. on. the sheet.

Immediately after the sheet is gripped, lifted and, stretchedby thev suction devices as. described,v said sheet is transferred to and taken. by mechanical grippers. on the chain gripper units 45, 46 of the upright conveyor hereinafter described, at which time the suction devices are released from the sheet, and continue. to move farther upwardly and outwardly to positions clear of the side edges of said. sheet. It is to be noted that by virtue of the cam arm 138 and the relative outward or retracting movement of the. rod 134 and suction device effected by said cam arm, the overall length of the-lever 133 from the axis 126 to the extreme end. of the suction device is in efiect shortened as said suction device moves farther upwardly and outwardly after release. of the separated sheet, thus requiring less upward stroke of each suction device to bring it to a position. clear of the side edge of the sheet. After the separated sheet is taken by the mechanical grippers, on the chain gripper units 45, 46 and before said sheet is completely removed from the top of the pile of sheets 20, the. combining wheels 127 and the suction devices are returned. beneath the separated sheet, for action thereof 'on the next sheet in the next cycle of operation of the feeder. In this manner, each succeeding sheet is separated, lifted and stretched while still partly covered by a previously separated sheet and is taken by the upright conveyor and removed from. the pile 20. in underlapped relation with the preceding sheet, with the result that the sheets are advanced by the upright conveyor in underlapped relation and. in the form of a. continuous stream thereof, as shown diagrammatically in Fig. 19.

In order to control the extent of downward movement of each suction device so that the suction cup 140. thereof will engage the humped corner portion of the, sheet at its separated level and not depress said portion back onto the pile 20, each rock shaft 126 has adjustably secured thereto for rocking movement therewith a finger 195 which is located adjacent to and rearwardly of the lever 133 (Figs. 6, 8 and 9). This finger 195 extends inwardly from the shaft 126 and is adapted to engage the top of the pile of sheets 20 when the suction cup 140 contacts the separated humped corner portion of the sheet, thus holding the shaft 126 against further rotation and the suction device against further downward movement by the spring 133-.

Vacuum is. created in the suction devices at predetermined intervals through flexible conduits 196 (Figs. 1 and 6.) having corresponding ends connected to the fittings 139 and opposite ends connected to the vacuum side of a rotary valve mechanism 197 which is suitably secured to. the =crossbar 38 for movement with the vertically movable. separator carriage. This valve mechanism 197 is of the general type disclosed in the United States. Patent No. 2,333,934, granted March 4, 1941, to Headley Townsend Backhouse, and needs no. detail description herein, except, to say that said mechanism is suitably connected to. a vacuum pump (not shown), and the rotor thereof is engaged over and suitably connected to the single revolution shaft 66, for rotation thereby to control the. making and breaking of vacuum in the cylinders 141 of the suction devices.

The chain gripper units 45 and 46 of the upright conveyor for receivingthe, sheets successively separated from the top of the stationary pile of sheets 20. and for. advancing said sheets from said pile in an upward direction are constructed one right-hand and the other left-hand, and since the constructions of said units are otherwise identical, a description of one will suffice for both. As herein shown, each chain gripper unit 45 and 46 is preferably constructed, mounted and operated as follows. Slidably mounted. on the. single revolution shaft 60 and drivably connected, as by a key and keyway connection, to said shaft for continuous rotation thereby. is a sprocket 171 around which passes an endless roller chain (Figs. 1, 10 and 19).. The chain 150 is arranged and guided, to travel ina fixed closed path defined by a straight upwardly travelling rear run located adjacent the front side of the stationary pile: of sheets 20 and extending from the bottom of the feeder to the top thereof and terminating in a forwardly curved, forwardly travelling, downwardly and, forwardly inclined run extending to the sprocket 171, a downwardly and rearwardly travelling run extending from the sprocket 171 and terminating in a straight downwardly travelling front run extending to the bottom of the feeder, and a semi-circular run at the bottom of the feeder connecting said front and rear runs and leading from one to the other.

For this purpose, each chain gripper unit 45, 46 includes an upper bracket 152 which is slidably mounted on the crossbar 29 and is provided with a suitable hearing to receive the shaft 60; This bracket 152 carries the bearingfor the upper end of the unit adjusting shaft 44 hereinbefore described; The bracket 152 encloses the sprocket 17.1., and is provided with an outer guide track which is engaged by the rollers of the chain 150 and which, as shown in Fig. 10, is formed of several curved and straight elements secured to said bracket in abutting relation for guiding said chain and causing it to travel in, the above described path. The bracket 152 has also secured thereto inner track elements 162, 164

and 166 which are engaged by the rollers of the chain 150 and cooperate with the guide track 170 to constrain said chain and assure movement of the latter in the above described path. Secured to the bracket 152 and extending downwardly therefrom is an upright bar 176 (Figs. 10, ll, 12 and 14) having secured thereto two upright track bars 177 which are engaged by the rollers of the chain 150 and serve to guide the front run of said chain for straight-line downward movement, said bars forming continuations of the guide track 170 and the track element 164. The bar 176 is undercut to provide sufficient clearance for the connecting-link-plates of the chain 150 at one side thereof. Secured to the bracket 152 and extending downwardly therefrom is an upright bar 178 having secured thereto two upright track bars 179 which are engaged by the rollers of the chain 150 and serve to guide the rear run of said chain for straight-line upward movement, said bars forming continuations of the guide track 170 and the track element 166. The bar 178 is undercut to provide sulficient clearance for the connecting-link-plates of the chains 150 at one side thereof, and said bar has also secured thereto a relatively wide upright pile positioning bar 193 which extends the full length of the, bar 178 and against the wide face of which the pile of sheets 20 is loaded in position for accurate feeding of the sheets from the top thereof. The rear face of the bracket 152 is suitably formed to provide an upward extension of the pile positioning bar 193.

The support bars 176 and 178 of each unit 45, 46 are secured at their lower ends to a bracket 194 which is slidably engaged over the crossbar 31. This bracket 194 carries the bearing for the lower end of the unit ad,

justing shaft 44 hereinbefore described. Secured to the bracket 194 is another bracket 198 which has secured thereto two concentric semi-circular track elements 199 which are engaged by the rollers of the chain 150 and serve to guide said chain and cause it to travel in a semi-circular path from the front trackway defined by the bars 177, 177 to the rear trackway defined by the bars 179, 179. The bracket 198 is undercut to provide sutficient clearance for the connecting-link-plates of the chain 150 at one side thereof, and said bracket is mounted on the bracket 194 for vertical adjustment so that any slack in the chain may be taken up and the desired degree of tightness of said chain may be obtained. To enable vertical adjustment of the bracket 158 the latter is provided with a suitable elongated clearance opening through which the crossbar 31 extends.

The chain 150 of each unit 45, 46 is provided at intervals therealong with a plurality of mechanical grippers indicated generally at 151 (Figs. 1, l0, l5, l6, l7 and 19). These grippers 151 are equally spaced apart along the chain 150 and such that the distance between the same is equal to the distance desired between the leading or front edge of a preceding sheet and the leading or front edge of a succeeding sheet on the upright conveyor, said distance being less than the length of the shortest sheet which the feeder is designed to handle, whereby the sheets as they are carried upwardly from the pile 20 hang in underlapped relationship as diagrammatically indicated in Fig. 19. The sprockets 171 are so chosen that for each complete revolution thereof, i. e., for each cycle of operation of the feeder, the chains 150 will be advanced a distance equal to the distance between successive grippers 151, whereby successive sets of said grippers will pass in position to receive successive sheets separated from the top of the pile 20 during successive cycles of operation of the feeder.

As shown particularly in Figs. l0, l and 16 of the drawings, each mechanical gripper 151 comprises a plate 153 which is provided at one side thereof with two pins located thereon as at 154 and 155 and which are of the same pitch as the chain 150 and pass through corresponding links of said chain in place of the standard chain pins. Pivotally mounted at 154 on the other side of the plate 153 is a gripper jaw 156 having pivotally mounted thereon at 157 a companion gripper jaw 158. Pivotally connected as at 158 to the jaw 158 is one end of a short rod 159 the opposite end of which extends loosely through a suitable opening in the jaw 156. Surrounding the rod 159 is a coil compression spring 159 having one end thereof engaging against the head of said rod and the opposite end engaging against a surface of the jaw 156. The gripper jaw 158 is thus normally urged by the springpressed rod 159 into close contact with the gripper jaw 156. Eccentrically pivoted to the gripper jaw 156 as at 156' is one end of a short rod 165 the opposite end of which extends loosely through a suitable opening in a block 153' which is rotatably carried by the plate 153. Surrounding the rod 165 is a coil compression spring 165' having one end thereof engaging against the head of said rod and the opposite end engaging against the block 153.

It will thus appear that by the described arrangement of the parts, the gripper jaws 156 and 158 are capable of rocking movement as a unit in opposite directions about the pivotal axis 154 relative to the chain 150, and the gripper jaw 158 is capable of rocking movement in opposite directions about the pivotal axis 157 relative to the gripper jaw 156 to opened and closed positions. It will also appear that the gripper jaw 156 and the springpressed rod 165 form in effect a toggle joint, and when said jaw is rocked by means to be presently described in one direction about the pivotal axis 154 thereof and the pivotal axis 156' of said rod passes the axis 154, the springpressed rod 165 operates to move the gripper jaws 156, 158 farther in said direction by a snap action to bring said jaws from the positions thereof shown in Fig. 16 to the positions shown in Fig. 15. Similarly, when the gripper jaw 156 is rocked in the opposite direction from the position thereof shown in Fig. 15, and the pivotal axis 156 of the spring-pressed rod 165 passes the axis of the block 153, said rod operates to move the gripper jaws 156, 158 farther in said direction by a snap action. Rocking movement of the gripper jaw 156 and therewith the gripper jaw 158 is limited in one direction through engagement of a surface 167 on the jaw 156 with a stop pin 168, and in he opposite direction through engagement of a surface 169 on said jaw with said pin, the latter being secured in the carrier plate 153. The gripper jaw 156 has journalled thereon at 156 a roller 160, and the gripper jaw 158 has journalled thereon at 161 a roller 161. The gripper jaw 156 has also journalled thereon at 154 a roller 163.

As previously stated, the cam units 40 and 41 are carried by and movable vertically with the separator carriage, and said units have fixed thereon for vertical movement therewith gripper introducing and opening cam blocks 174 (Figs. 1 and 17) which are disposed in the paths of upward movement of the grippers 151 on the chains 150. Each of the cam blocks 174 is constructed to provide a lower inclined cam surface 181 and an upper reversely inclined cam surface 182. Disposed at the tops of the chain gripper units 45, 46 and in the paths of forward movement of the grippers 151 on the chains are gripper opening cam bars 172. Secured to the brackets 198 on and at the bottoms of the chain gripper units 45, 46 are gripper tumbling or turnover cam bars 173 which are disposed in the paths of downward movement of the grippers 151 on the chains 150, each of said cam bars being constructed to provide an upper inclined cam surface 173'.

Referring now to Fig. 17 of the drawings, which diagrammatically illustrates the gripper circuit and shows one gripper or one set of grippers 151 in the various positrons it occupies as it travels around said circuit, let it be assumed that said gripper or set of grippers is travelling upwardly from the bottom of the feeder towards the top of the stationary pile of sheets 20 adjacent to but clear of the front side of said pile. At this time the gripper 151 is closed and the surface 167 of the jaw 156 is engaged with the pin 168, thus positioning the jaws 156, 158 that the bite thereof is substantially horizontal. As the gripper 151 reaches the top of the pile of sheets 20 at whatever level it may be, the roller 161 on the jaw 158 rides upwardly past, and out of contact with, the lower cam surface 181 of the cam block 174, and as the gripper 151 continues to move upwardly, the roller on the jaw 156 engages and rides upwardly along the lower cam surface 181 of the cam block 174 and the roller 161 on the jaw 158 simultaneously engages and rides upwardly along the upper cam surface 182 of said cam block. Under these conditions the jaws 156, 158 are rocked as a unit rearwardly about the axis 154 towards the separated, lifted and stretched sheet 185 by the combined actions of the cam block 174 and the spring-pressed toggle rod 165, and the jaw 158, through such rocking movement thereof with the jaw 156 and engagement of the roller 161 with the cam surface 182, is caused to rock about its axis 157 farther away from the jaw 156, thus fully opening the grippers 151 and introducing the jaw 156 beneath the lifted and stretched front edge portion of the sheet and projecting the jaw 158 over said sheet portion. Thereafter, as the gripper 151 continues to move upwardly, the roller 161 on the jaw 158 rides off the cam surface 182 of the cam block 174, whereupon said jaw is rocked about its axis 157 toward the jaw 156 by the spring-pressed rod 159 to firmly grip the sheet 185 between the same and the jaw 156. During the described gripper opening and introducing operations the gripper 151 is steadied through engagement of the rollers of the chain 17 .150 with theztr-ack bars 179 and engagement of the roller 163 with a surface 175 on the respective ream After the front edge portion of therseparated, litted and stretched sheet 185 is gripped by the transversely aligned set of grippers 151, said sheet, through continued upward movement of. said grippers, is withdrawn from the top of the stationary pile 20 and advanced upwardly to :the top of the gripper circuit. During :this upward movement of the grippers 151 and .the sheet 185 gripped thereby, said grippers arecaused to gradually .rock about the axes 154 downwardly towards the ,pile of sheets 20, whereby each gripper will assume a position such that the bite thereof more nearly approaches vertical position and thus conforms to the vertical attitude of the hanging sheet 185 gripped thereby. For this purpose, each chain gripper unit 45 and 46 includes a bar 190which is secured at its lower end to a bracket 190' which, in turn, is pivotally mounted as at 191 on the bracket 194. The bars 190 extend upwardly to substantially the top of the crossbar 29 and are normally tilted forwardly at a slight angle with respect to the straight-line vertical upward movement of the chains 150 and the grippers 1'51 thereon. The bars 190 pass through and are guided in suitable bifurcated portions of the cam units 40, 41, and they engage adjustable balls 192 loosely carried in suitable sockets in said units.

It will thus .appear that when the .grippers 151 are rocked by the combined actions of the cam blocks I74 and the spring-pressed toggle rods 165 .rearwardly into positions to grip the sheet 185 as above described, the rollers 160 on the gripper jaws 156 engage the .bars '190 and are held in engagement with said bars under .the influence of the toggle rods 165. Accordingly, as the grippers 151 travel upwardly with the gripped sheet 18510 the top of the gripper circuit, the rollers 160 being under the (influence of the spring-pressed toggle rods 165 are caused to follow the inclined bars 190 and in so doing permit said grippers to progressively rockin a downward direction under the influence of said toggle rods an extent permitted by said bars. The degree of rocking movement of the grippers 15:1 which is requiredin conformity with the inclination of the bars 190 varies in accordance with the distance between the top of the pile of sheets and the top of the gripper circuit, i. e., according to the height of the pile. In order to achieve this variation the inclination of the bars 190 is adjusted in accordance with the elevated position of the cam units 40 and 41. This result is obtained by supporting the backs of the bars by adjustable balls 192 which rise and fall with the cam units and against which the bars 190 are pressed by the gripper rollers 160.

The sheet 185 takenby the grippers 1 51 is advanced upwardly to the top of the gripper circuit and then forwardly and delivered to the tape conveyor 21 between the latter and co-operating pressure rollers 203, "at which time the grippers are opened to release said sheet for further movement by said conveyor toward the printing press or other machine with which the feeder is associated. As the grippers 151 enter the path of forward movement thereof they assume a natural positi'on in which the bites of the jaws 156, 158 are trailing and are substantially tangential to said movement. Opening of the grippers 151 after the sheet 185 is delivered to and between the tape conveyor 21 and pressure rollers 203 is efiected by the cam bars 172 which are so positioned in the path of forward movement of said grippers that the rollers 160 on the jaws 156 pass beneath said bars, and the *rollers 1 61 on the jaws 158 pass above said cam bars. The opening of the grippers is effected by humps 172 on the cam bars 172, which humps lift the rollers 161 on the upper jaws 158 as they pass along the cam bars and so open the travel around the sprockets 171 which occurs after the sheet 185 is delivered between the tape conveyor 21 and the pressure rollers 203. As the grippers 151 continue 1 8 toz-move :downwardlyaround the sprockets 17-1, the rollers .151 on the gripper jaws .158 move out of engagement Withthe cam-bars 172, whereupon said grippers are again closed by the action of the spring-pressed rods 159 on said .j-aws. The grippers 151 then continue to move downwardly to the bottom of the feeder in a natural position in which the bites of the jaws 156, 158 are trailing and are substantially vertical.

As the grippers 151 approach the bottom of the feeder and before they enter their semi-circular path and begin their upward movements to .act on another sheet separated from the top of the pile 20,the rollers 160 on the jaws 156 engage and ride downwardly along :the cam surfaces 173' of'the cam bars 173, whereupon said grippers are, through the combined actions of said cam bars and the spring-pressed toggle rods 165, tumbled or turned-over approximately .90 about their axes 154 from the positions thereof :in which the bites of the jaws .156, 158 are vertical to positions in which said bites are horizontal and the jaws 158 are leading, as shown in Fig. 17, thus resetting the grippers'for action on another sheet as the same again travel upwardly past the top of the pile of sheets v20. The described gripper operations are repeated for each set of grippers as the same travels along the described Zgipper circuit, whereby sheets separated successively from the top of the pile 20 are taken by successi-ve sets of gripers, removed from said pile, and advanced upwardly in lapped relation, as shown diagrammatically in Fig. 19. It is to be noted that by virtue of the described upward removal of the sheets from the top or the pile .20, -a relatively wide space .is immediately created between the topmost sheet being removed and the next sheet on said pile, which space advantageously enables immediate return of the combing wheels 127 and the suction devices beneath said topmost sheet, and performance of the separating, lifting and stretching operations on said next sheet while the latter is still partly covered by the outgoing topmost sheet.

To fiacilitate the .movement of the sheets in the forward direction, guide brackets @200 (Figs. 1 and 18) are slidably mounted on the crossbar 29 inwardly of the chain gripper units 45, 46. These guide brackets 200 are laterally spaced from (the chain gripper units and are secured to the upper brackets 152 of said units by means of bolts 204*and 205.,..the bolts 204 passing through suitable clearance openings in the brackets 152 and being threaded into spacer brackets 206, and the bolts 205 passing throughsuitable clearance openings in the brackets 152- and- .206 and being threaded .into the brackets 200. The guide brackets 200 carry .the gripper opening cams 172 and the outline of said brackets is similar to the outline of the brackets 152 in conformity with the path of forward travel of the sheets. To further support and guide the sheets in the forward movement thereof onto the tape conveyor 21, other curved guide brackets 207 are adjustably secured to the crossbar 29 between the guide brackets 200.

The tape conveyor 21 comprises a plurality of transversely spaced endless tapes 202, two only being shown, which travel over and along .a feedboard 201 suitably supported on the feeder frame. The rear portions of the tapes 202 pass around and are driven 'by flanged pulleys 208 (Fig. 18) which are disposed between the brackets 152 and 200 and are keyed to the shaft 60 for rotation thereby and for sliding movement along said shaft. The tapes 202are driven at the same surface speed as that of the grippers 151.50 that the lapped relation of the sheets is maintained as said sheets are further advanced by the conveyor 21 to the printing'press or other machine. The rear portions of the tapes 202 also pass over and around idler rollers 209 journalled at 210 on the guide brackets 200, and over and around tape tightening rollers 211 which are journa'lled as at 212 on the upper ends of arms 213 which are pivotally mounted at 205 on the spacer.

brackets 206. The arms 213 have connected therewith corresponding ends of coil extension springs "214 the opposite ends of which are connected as at 215 to the guide brackets 299. The pressure rollers 203 are journalled on arms 216 which are adjustably secured on a shaft 217 that extends transversely of the feeder and is rotatably carried by the upper side frame brackets 26. The pressure rollers 293 rest by gravity on the tapes 202, augmented by a coil extension spring 218 having one end thereof connected to a rod 219 which extends through and is secured in one end of the shaft 217, said rod being utilized to manually lift said pressure rollers out of engagement with said tapes and the sheets carried thereby. The opposite end of the spring 218 is connected to the adjacent upper side frame bracket 26.

The operation of the feeder will be clearly understood from the foregoing description and may be briefly summarized as follows. The continuously rotating combing wheels 127 are lowered onto the top of the stationary pile of sheets 26 and comb the front corner portions of the top sheet inwardly towards each other whereby small buckles or humps are formed in said sheet adjacent said corners and the sheet is separated from the next or underlying sheet at opposite front corners thereof. During this combing operation, the feeler 7i) and presser fingers 142 are resting on the top of the pile, and the suction devices are being lowered towards said pile. When the combed top sheet is engaged and gripped at the humped corner portions thereof by the suction cups 140, the combing wheels 127 are raised to the broken line positions thereof shown in Fig. 7 clear of the side edges of said sheet, and the feeler 70 and presser fingers 142 are raised to positions clear of the front edge of the sheet. The suction devices are then raised to lift and stretch the entire front edge portion of the sheet which is then gripped by a set of upwardly travelling grippers 151 at spaced points along said edge and removed from the pile in an upward direction. When the lifted and stretched front edge portion of the top sheet is gripped by the grippers 151, said sheet is released by the suction cups 145) through the breaking of vacuum therein, and the suction devices are further raised to the broken line positions thereof shown in Fig. 8 clear of the side edges of the upwardly moving sheet. While the top sheet is being removed from the pile by the grippers 151, the feeler 70, the presser fingers 142, the combing Wheels 127 and the suction devices return beneath said sheet and the next sheet is separated, lifted and stretched at the front edge thereof and is taken by the next set of upwardly travelling grippers 151 before the preceding sheet has been completely removed from the pile so that there is formed on the upright conveyor a stream of lapped sheets which is delivered to the tape conveyor 21 and is advanced by said tape conveyor to the printing press or other machine which takes the forward uppermost sheets successively from said stream for performance of printing or other operations thereon.

As the height of the stationary pile of sheets 20 decreases through feeding of sheets from the top thereof, the sheet separating mechanisms 39 are automaticaliy lowered, the cyclic timing of the operations of said mechanisms is automatically advanced in relation to the movement of the sets of grippers 151 and the advanced arrival thereof at the changing level of the gradually diminishing pile, and the sheet taking operations of said grippers are automatically controlled to occur as the grippers travel past said changing pile level, whereby separation of the sheets successively from the top of the pile and removal of said sheets from said pile is maintained and assured throughout the entire run of the pile of sheets and until said pile is exhausted.

A modified form of drive is illustrated in Fig. 20 of the drawings, which drive may be used in lieu of the described drive comprising the chain 57 and sprocket 65, for rotating the shaft 66 and for efiectively advancing and retarding the cyclic timing of the operations of the sheet separating mechanisms 39 as the latter are lowered and raised,

respectively. This modified form of drive is designed to rotate the shaft 66 one complete revolution at timed inter-- vals and in timed relation with the operation and cycle of movement of the upright conveyor comprising the chains and the sheet grippers 151 thereon. As shown, the modified form of drive comprises a spur pinion 225 which is fixed on the shaft 66 in place of the previously described sprocket 65. This pinion 225 meshes with and is driven by a spur gear 226 which is fixed on a short transverse shaft 227 having one end thereof supported by and journalled in a suitable bearing provided in the guide block 35 of the vertically movable separator carriage. The opposite end of the shaft 227 is supported by and journalled in a suitable bearing provided in a bracket 228 which is secured to or formed integrally with the guide block 35 of the vertically movable separator carriage. Hence, the gear 226, shaft 227 and bracket 223, through the described mounting thereof on the guide block 35, are caused to move vertically with the separator carriage which, as previously described, also carries the shaft 66 on which the pinion 225 is fixed. The ratio of the pinion 225 and gear 226 is 2:1 such that said pinion will make one complete revolution to each onehalf rcvolution of said gear.

Secured to or formed integrally with the gear 226 is a. disk 229 provided with two slots 23% disposed diametri cally opposite each other and opening radially through the periphery of said disk. Spaced axially from the disk 229 and fixed on the shaft 227 is a second disk 231 provided with two slots 232 disposed diametrically opposite each other and opening radially through the periphery of said disk, said slots being aligned with the slots 23% in the disk 229. Disposed between the disks 229 and 231 and rotatably mounted on the shaft 227 is a sprocket 233 around the front half of which passes the rear reach of an endless chain 234 which is used in place of the previously described driving chain 57. The chain 234 at the upper end thereof passes around and is driven by the previously described driving sprocket 53, and also passes at said end over and around the previously described idler sprockets 54 and 56. The chain 234 at its lower end passes under and around the previously described guide sprocket or disk 55. The chain 234 will thus be driven by the sprocket 53 continuously and in the same direction and at the same surface speed as that of the chains 15% of the upright conveyor gripper units 45, 46. The rear upwardly travelling reach of the chain 234 is guided around and maintained in engagement with the sprocket 233 by a guide plate 235 which is secured to the bracket 228. This guide plate 235 leads the chain 234 through a gentle curve on to and away from the sprocket 23.3. thus reducing the acceleration and deceleration of the disks 229, 231 and of the shaft 66.

The chain 234 is provided at intervals therealonr: n

. a d at opposite sides thereof with a plurality of rollers 236 which are equally spaced apart so that the distance be tween the rollers is equal to the distance between the grippers 151 on the chains 150 of the upright conveyor gripper units 45, 46 the rollers on one side of the chain 234 being in alignment with the rollers of the other side of said chain. It will thus appear that as each pair of rollers 236 on the continuously moving chain 234- is about to pass around the sprocket 233, said rollers will enter the lower pair of radial slots 230, 232 in the disks 229, 231 and through movement thereof around said sprocket and engagement with said disks in said slots will rotate the disks 229, 231, the gear 226 and the shaft 227 one-half of a revolution and then pass out of the slots. 230, at the tops of said disks, thus rotating the shaft 66 one complete revolution through meshing engagement of the pinion 225 thereon with said gear. When the disks 231 are rotated one-half of a revolution as described, the opposite pair of slots 230, 232 in said disks are brought into position for engagement by the next pair of rollers 236 on the chain 234 in the next cycle of operation of the :feeder. The phase TdatlOHFdf thezoperation ofztherollers 236-to :the operation andrcycle ofmovement of the grippers 151 is :so chosen to effect rotation of the shaft 66;an.d

operation ofthe sheet separating mechanisms 39 at the appropriate time, and it .Will be noted that this phase relation will remain constant during the vertical movements of .the sheet separating mechanisms, whereby the sheets will alwayslbe separated-from the top of the stationary pile .20 in time r'fOI engagement by the grippers 151 as the latter travel :upwa-rdly past thechanging level of saidpile.

In order toguard against accidental rotation of the shaft 66 during the interval -between:operations of said shaft, one of the .:disks, i. e., :the disk 229, is provided with two axially :projectingpins237 which are disposed diametrically opposite each-other and centrally between the radial slots 230. The.1pins;237 are arranged to clear the .pinion .225 upon .rotationof the disks 229,231, and to enter between the :OPPOSCd ends of two vertically aligned locking .pawls 258 .and 23.9 vatthe end of each half revolution of said .dis'ks. The {pawls 238 and 239 areipivotally mounted as at 240;-and 241,,respectively, on the bracket 228, and said pawls are so shaped that when the rollers 236 on the chain 234 begin to enter the radial slots 230, 232 in the disks 229., .231, oneof said rollers will engage the. pawl 238 and rockthe same out of the path of rotation of the pm 237" engaged therewith .and thus release said disks for'rotation. When theroller 236 moves out of engagement with'the pawl 238, the latter immediately returns to its original position for engageeachpin 237 approaches the pawl 238-it deflects the pawl 239out of its path, which pawl .239then-immediately returns to its original position above said pin when the latter contacts the upper end ofthe pawl 238. The pawls 238, 239 cooperate to releasablyglock the disks .229, 231

against rotation in both directions.

In Figs. 21 and 22 of the drawings there is :shown a modification of the intermittent drive shown in Fig. 20.,

said modification'utilizing the hereinbefore described drive chain 234, and comprising similar elements similarly operated, but constructed and mounted as follows. Spaced outwardly from the guide block 35 of the vertically movable separator carriage .and suitably secured:to said block for vertical movement with said carriage is a guide plate .250 which surrounds a guide wheel .251 that .is rotatably mounted on a sleeve 252 which is engaged over and rotatably mounted on the .projectinggear side end of the shaft 66. The guide plate :250 :serves 'to .guide the rear upwardly travelling reach of the chain 234 around onehalf of the periphery of the guide wheel'251 and is providedat the bottom :thereof with an entrance slot 253 i for directing :said chain reach in a gentle curve to said wheel, .and at the top thereof with an outlet slot 254 for leading said chain reach in a gentle curve away from said wheel. Spaced axially'from the guide wheel 251 and guide plate 250 and secured to the sleeve 252 at opposite sides of said wheel and said plate'are identical disks 255 each of which is provided with four radially extendingslots 256 which are spaced 90 apart and open outwardly through the .peripheryof the disk. 1

Secured to the sleeve 252 adjacent the inner disk 255 is a gear 257 which meshes with and drives -a gear 258 that is rotatably mounted on the projecting gear-side end of the tubular crossbar .37 of the separator carriage. Secured to or formed integrally with the gear258 is a gear 259 which meshes with and drives a gear'260*that:is'fixed on and drives the shaft 66. The combined ratio .of the gears 257, 258, 259 and 260 is such that the gear .260 fixed "on the shaft 66 i will make one complete revolution to each three-quarters of i a revolution of the gear .257.

in :the :normal position ofthe disks 255, :two of the 'radial i 22 .slots25'6'thereof are inregister with-theslots 253 and 254, :respectively, of .theqguide plate 250].

.Itwill thus appear that as each pair 'of'rollers 236 on vthe continuously moving chain 234 is about the pass around-the guide wheel 251,'said rollers will radially-enter the lower pairof radial slots 256 of the disks 255 and in passing around-the curved portion of the slot 253of the guide plate 250 will initially rotate said disks in the -.direction of :the arrow indicated-in Fig. 21 at a gradually increasing speed through engagement of said rollers with said disks in the slots 256 thereof. Asthe rollers 236 proceed around the guide wheel 251 the disks 255 are further rotated by said rollers at a constant speed, and as [12116 1 011613.2156 leave said guide wheel and travel along the curved portion of the-slot 254 of the guideplate 250 and out of the slots 256 of said disks, the speed ofthe disks 255 is gradually reduced and said disks are stopped. This occurs when the disks 255 have completed threequarters of a revolution, thus resulting in rotation of the shaft 66 one complete revolution in the direction ofthe arrow indicated in 'Fig. 21 through the described gearing between said disks and said shaft. When the disks 255 are rotated through three-quarters of a revolution and stopped as described, another pair of slots 256 of said disks is positioned to receive the next pair of rollers 236 on the chain .234 in the next cycle of operation of the feeder.

To. guard against accidental rotation of the shaft 66 duringthe interval between operations of said shaft, the shaft has fixedthereon an arm 261 provided at its free end with a pin 262. This pin 262 is arranged to engage between the opposedends of two vertically aligned locking pawls 263 and .264 at the end of each complete revolution of the shaft 66. The ;;pawls 263 and 264 are pivotally .mounted at 265 and 266, respectively, on the guide plate 250, and said pawls are so shaped that when the rollers 236'on thechain 234 begin to enter the radial slots 256 of *the disks 1255, one of said rollers will engage the pawl .263 and rock thesame out of the path of rotation of the pm 262 and thus release the shaft 66 for rotation. When the roller 236- moves outof engagement with the pawl 263 .and'the shaft 66 begins to rotate, said pawl is immediately returned .by. a coil extension spring 267 to its original operative position determined by a stop pin 268 carried by the guide plate 250 and engaged by said pawl. The spring 267 has one end-thereof connected to the pawl 263 and the oppositeend connected to the stop pin 268. Just before therollers 236 begin to'leave the radial slots 256 of the disks255, one of said rollers will engage the pawl 264 and rock the same out of the path of rotation of thev pin 262 as the latter approaches the pawl 263. When the roller i236 moves out of engagement with the pawl 264 the latter is immediately returned by a coil extension spring269 to its original operative position above the :pin 262 determined by a stop pin 276 carried by the guide .plate 250 and engaged by said pawl. The spring 269 has one .end thereof connected to the pawl 264 and the opposite end connected to the stop pin 270. The pawls .263, 264 cooperate to releasably lock the shaft 66 against rotation in both directions.

In another modified form of separator drive shown in Fig. 23 of the-drawings, a vertically extending drive shaft .271 may -be effectively employed in lieu of the described chaindrive shown in Figs. 1, 20, .21 and 22. This drive shaft 271 is arranged to extendlabove and below the range of upward and downward movements of the separator carriage and is suitablyjournalled in bearings carried by the feeder-frame at the gear side thereof, said bearings also serving to hold said shaft against axial movement in either direction. The shaft 271 is provided substantially along the entire length thereof with a helical keyway or groove 272 of such design that the pitch of the helix is equal to .the distance between adjacent sheet grippers i151 on thechains'1'50of the upright conveyor. A bevel gear mounted onsthe shaft 271 for sliding movement therealong and is drivably connected to said shaft for rotation thereby by a key 274 carried by said gear and slidably engaged in the helical keyway 272. This gear 273 is rotatably carried by an extension of the guide block 35 of the separator carriage and is connected in a suitable manner to said guide block so that it moves vertically with said carriage. gear 274 which is fixed on and drives the shaft 66 which, as hereinbefore described, drives the sheet separating mechanisms 39. The gears 273 and 274 are of the same size and, hence, the ratio of the shafts 66 and 271 is 1:1. Other ratios may be used provided that the single revolution of the shaft 66 is maintained and that the pitch of the helical keyway 272 is appropriately chosen. The shaft 271 is appropriately and continuously driven from the hereinbefore described shaft 60 in a suitable manner and by suitable driving means connecting said shafts including a bevel gear 275 or the like fixed on the upper end of the shaft 271.

It will thus appear that the described drive provides for continuous rotation of the shaft 66 and operation of the sheet separating mechanisms 39 in all vertical positions of the separator carriage. It will also appear that the bevel gear 273, by virtue of the helical keyway 272 in shaft 271, will be rotated in one direction relative to said shaft as the separator carriage is lowered, and will be rotated in the opposite direction relative to the shaft as said separator carriage is raised. Accordingly, each time the separator carriage is lowered, the shaft 66 is given a degree of forward rotation commensurate to the extent of downward movement of said carriage, thus correspondingly advancing the timing of the operations of the sheet separating mechanisms 39, and when the carriage has been lowered a distance equal to the spacing between the sheet grippers 151 the shaft 66 will have been advanced one complete revolution, thereby maintaining the timing relationship of the sheet separating mechanisms with the operation and cycle of movement of the sheet grippers. Similarly, when the separator carriage is raised a distance equal to the spacing between the sheet grippers 151, the shaft 66 is given a backward rotation of one complete revolution, thus correspondingly retarding the timing of the operations of the sheet separating mechanisrns relative to the operation and cycle of movement of said sheet grippers.

Various other changes in or additions to the described feeder structure may be made. For example, the feeder driving shaft 43 may be driven so that it rotates one complete revolution for each cycle of operation of the feeder, and the sprockets 53, 65 and 171 accordingly selected and proportioned so that the shaft 65 will rotate one complete revolution for each feeding cycle, and that the conveyor chains 153 will be advanced a distance equal to the spacing between the sheet grippers 151 thereon for each feeding cycle. The upright conveyor may be of the gripper-bar type wherein the gripper jaws are mounted on separate transversely extending bars disposed between and carried by the chains. Also, preliminary separation of the topmost sheet may be effected by air blast devices, in lieu of the combing wheels, said air blast devices being arranged to direct blasts of air at and diagonally across the front opposite corners of the pile of sheets. Or, in lieu of the combing wheels, fingers may be employed at opposite sides of the pile of sheets to lift the corner portions of a plurality of the uppermost sheets for engagement of the topmost sheet at its elevated corner portions by the suction devices and stretching of the entire front edge portion of said sheet by said devices through outward movements thereof with or without any upward movement, said fingers releasing the remaining sheets to fall away from the topmost sheet and back on to the pile when said topmost sheet is gripped by the suction devices.

If desired, the forward extension of the upright conveyor may be eliminated, the chains of the upright conveyor then terminating at the top of the gripper circuit The gear 273 meshes with a bevel 24 and passing around sprockets which are fixed on an equivalent driving shaft having a drum or an equivalent series of disks thereon around which the sheets are advanced to the tape conveyor. On the other hand, the tape conveyor may be eliminated by extending the forward extension of the upright conveyor.

The feeder may also be employed as a sheet by sheet feeder to feed sheets singly in spaced relation by simply increasing the surface speed of the upright chain conveyor and the horizontal tape conveyor, and by spacing the sets of grippers on said chain conveyor further apart, in accordance with the maximum size sheet to be handled.

Although only a single embodiment of the present invention has been illustrated in the accompanying draw- I ings anddescribed in the foregoing specification, it is to be expressly understood that the invention is not limited to said embodiment. Various changes may be made in the mechanical details, some of which have been illustrated, described and suggested herein, without departing from the spirit and scope of the invention, as will now be apparent to those skilled in the art. For a definition of the limits of the invention reference is had primarily to the appended claims.

What is claimed is:

1. In apparatus of the character described, vertically positioned conveyor means arranged adjacent a supply of horizontally disposed sheets for taking an edge portion of a sheet of said supply presented thereto and removing said sheet from said supply in a straight upwarddirection thereby providing and maintaining a space between said sheet and said supply, means engageable with the top surface of an edge portion of the uppermost sheet of said supply for lifting said edge portion and positioning it for reception by said conveyor means, and means for operating said sheet engaging and lifting means and for causing the same to move beyond the margin of the sheet just positioned thereby and taken by said conveyor means and return into said space beneath said sheet into position to operate on the next sheet of said supply.

2. In apparatus of the character described, means for engaging the top surface of the uppermost sheet of a supply of horizontally disposed sheets and lifting an edge portion of said sheet, vertically positioned endless conveyor means arranged adjacent said supply for taking said sheet at its lifted edge portion from said sheet engaging and lifting means and removing said sheet from said supply in a straight upward direction thereby providing and maintaining a space between said sheet and said supply, and means for operating said sheet engaging and lifting means and for causing the same to move beyond the margin of the sheet just lifted thereby and taken by said conveyor means and return into said space heneath said sheet into position to operate on the next sheet of said supply.

3. In a sheet feeder, an endles conveyor having a substantially vertical reach arranged adjacent a supply of horizontally disposed sheets and extending upwardly beyond the top of said supply, means for driving said conveyor so that said reach travels in an upward direction, said conveyor including sheet gripping means for gripping edge portions of successive sheets separated successively from said supply and removing said sheets from said supply in an upward direction thus providing and maintaining a space between each sheet being removed and said supply, means for engaging the top surface of each uppermost sheet of the supply in turn and lifting an edge portion of said sheet into position to be gripped by said gripping means as the latter travels along said reach, and means for operating said sheet engaging and lifting means and for causing the same to move beyond the margin of the sheet just lifted thereby and gripped by said gripping means and return into said space beneath said sheet into position to operate on the next sheet of sai supply. t;

4. In apparatus of the character described, suction means engaging-the top :sur'face ofithenppermostxsheetof a supply of horizontallyrdisposed :sheets and lifting the front edge portion of=said sheet above the general "level of the top of said supply,.-a vertically positioned-endless chain conveyor arranged with garreach thereof adjacent said suppiy and extending rfrom afllevel below the top of said supply ;to a level above-said supply, means for driving said conveyor such that said preach travels in an upward direction, sheet 'grippers on said :conveyor comprising complementary jawsim'ovableasa unit relative to said conveyor towards said YSUPPIY and over the top thereof to grip the liftedtfront edge portion of the sheet at spaced points along the :same and remove said sheet from said supply in a substantial-lystraight-upward direction as said grippers travel alongisaid :reach :thereby providing and maintaining a space between said sheet and said supply, andmeans foroperatingsaid suction means and for causing the same'rtotmove beyond the margin of the sheet just lifted t-herebyand gripped'by said grippers and return into said space beneath said sheet jinto position to operate on the next sheetof said supply.

5. .In apparatus of the :character described, means for gripping the upper side of :a horizontally disposed sheet and lifting an edge ;portion=oftsaid sheet without advancing said sheet, and travelling gripper means constrained to travel in a straight upward rpath "for gripping the lifted sheet edge portion while in motion and advancing said sheet in a straight upward direction.

6. In apparatusof the character described, means for gripping "the upper surface of :a sheet disposed in horizontalposition and lifting an edge portion of' said sheet without'advancing said sheet, and ltravellinggripper means constrained to travelin-a straight upward path for gripping the lifted sheet edge portion while in motion and advancing said sheet in a straightupward direction with t and remove said sheet fromsaidasupply.

8. In a sheet feeder, means forsliftingran wedgeportion of a sheet to :partly separate :the same from the top of a supply of horizontally disposed sheets, and means for removing said sheet from said supply in asubstantially straight upward direction and comprisingzan endless chain arranged with a reach thereof adjacent said .supply and an edge portion of each sheet, and conveyor .means for removing in an upward :direction from-said sup ly the sheets successively lifted byI-said separating means, said conveyor means comprising endless means having a substantially vertical reach disposedkadjacent said supply and extending from a level below the top of said supply 'to a level above said supply, means for driving said endless means such that said reach travels in an upward direction, a series of sheet grippers mounted on tions on said jaw elements, andcam means cooperating with said projections as each gripper travels along said reach and passes the top of said supply for swinging the jawelements thereof in opened condition towards and over said supply andfor causing said jaw elements to close on and grip the lifted :edge portion of the top most sheet of said supply.

11. Apparatus as definedin'claim 10, comprising other biasing means actingzupon one'of the jaw elements of each sheet gripper as the latter travels upwardly with the sheet gripped thereby for turning the jaw elements thereof downwardly to a position such that the bite thereof is substantially vertical and conforms with the vertical attitude of the sheet suspended therefrom, and

other cam "means cooperating with one ojfsaid projections of each gripper for controlling the movement of the jaw elements thereof by saidother-biasing means to said position.

12. Apparatus as definedinclaim 110, comprising bias- 'ing means operably connected withand-applying a yieldextending vertically from a level below the top of said supply to a level above-sai'd supply, ia gripper. comprising complementary jaws mounted .on' said chain for movement therewith and pivotal movement:relativetoleach other and as a unit rel ativeto said-chain, biasing means acting upon one of said jaws and yieldingly urging the same toward the. other of said jaws, means for driving said chain such that said reach travels in an upward direction, operative elements connected to sa-id jaws, and cam means cooperating with said elements as said gripper travels upwardly'along said 'reach for opening said jaws and swinging the same towards an'd over :the top of said supply into positions with onejawdisposed above the lifted sheet edge portion andthe otherjaw disposed below said sheet portion and for causing sa id jaws to close on the sheet and grip the same.

9. A sheet feeder as 'defin'ed in --claim'8, comprising other cam means cooperating with one 'ofsaidelements during upward movemento'f the gripper with the sheet gripped thereby for positioning the jaws so ithatthe bite thereof is substantially vertical and conforms to the vertical attitude of the sheet suspen'ded therefrom.

10.111 apparatus of --the' character described, means for separating sheets successively from 'the "top of a supply of horizontally qdisposed sheets throughslifting of able forcev upon the first jaw element-of each sheet gripper as the latter travels upwardly with the sheet gripped thereby, said force being applied in :a direction-tending to rotate said jaWeIement and its companion jaw element downwardly, and means-arranged to he engaged by said first ljaw element for controlling the extent of downward rotation thereof by saidbiasing means whereby said jaw elements are so positioned that the bite thereof is substantially vertical and conforms to the 'vertical attitude of the .sheet suspended therefrom.

13. Apparatus asdefinedin claim .10, comprising a spring-pressed toggle'member operably connected with l and applying a yieldable force upon. the first jaw element of each sheet gripper:as the latter travels upwardly with the sheet gripped thereby said force being applied in a direction tending to rotate said jaw element and its companion jaw element downwar lynand a bar extending along and inclined with respect to .the .path of upward movement of the gripper.an d disposed in the path of rotation of said jaw elements by said toggle member for controlling the extentof said rotation whereby said jaw elements are gradually rotated to aposition such that the bite thereof is substantially vertical and conforms to the vertical attitude of the sheet suspended therefrom.

l4. Apparatusas defined inclaim 10, wherein the sheet grippers are spaced aparta distanceless than the length of the sheets so that eachsucceedingsheet being removed from the supply is lapped by :a precedi-ng sheet and the sheets are carried upwardly in.lapped relationship by said grippers.

thereto through a defined path including a straight vertical course arranged adjacent said supply, means for driving said chain such that said grippers travel upwardly along said course, said grippers each comprising a first jaw element pivotally mounted on said chain and a companion jaw element pivotally mounted on said first jaw element, biasing means operably connected with the companion jaw element of each gripper for yieldingly urging the same towards its associated first jaw element,

said grippers being closed and so positioned that the bites of the jaw elements thereof are substantially horizontalv as the grippers travel along said course towards the top of said supply, projections on the jaw elements of each gripper, cam means disposed in said course and cooperating at the locality of the top of said supply with said projections for swinging the jaw elements of each passing gripper towards and over said suppiy, opening said jaw elements to receive therebetween the lifted edge portion of the sheet, and permitting said jaw eiements to close on said sheet portion under the influence of said biasing means, other biasing means acting upon the first jaw element of each gripper as the latter travels further upwardly along said course with the sheet gripped thereby for rotating the jaw elements thereof downwardly to a position such that the bite thereof is substantially vertical, cam means cooperating with the projection on the first jaw element for controlling the movement of the jaw elements of each gripper by'said other biasing means to said position, cam means disposed in and cooperating at a further locality of saidpath with the projection on the companion jaw element for opening the jaw elements of each passing gripper to release the sheet, each gripper after release of the sheet returning along sait path to said course with the jaw elements closed arm the bite thereof substantially vertical and trailing, and cam means disposed in said path and in advance of said course and cooperating with the projection on the first jaw element for tumbling each passing and returning gripper to position the jaw elements thereof for subsequent upward movement along said course.

16. A sheet gripping and conveying device comprising an endless chain constrained to travel in a defined path, a sheet gripper comprising a first jaw element pivotally mounted on said chain and a companion jaw element pivotally mounted on said first jaw element, biasing means operably connected with said companion jaw element for yieldingly urging the same toward said first jaw clement, said gripper being closed and so positioned that the bite of said jaw elements is substantially at right angles to said chain as the gripper travels along one reach of said chain, projections on said jaw elements, cam means disposed in said path and cooperating at one locality of said reach with said projections for swinging said jaw elements relative to said chain towards a sheet to be gripped and conveyed, opening said jaw elements to receive the leading edge of said sheet therebetween, and permitting said jaw elements to close on and grip said sheet under the influence of said biasing means, cooperating spring and cam means respectively acting upon the first jaw element and arranged to be engaged by the projection on said first jaw element for rotating said jaw elements in the direction of the sheet gripped thereby to a position such that the bite thereof is substantially parallel to said chain reach as said gripper travels further along said reach, cam means disposed in and cooperating at a further'locality of said path with the projection on said companion jaw element for opening said jaw elements to release the sheet, said gripper after release of the sheet returning along said path to said reach with the jaw elements closed and the bite thereof trailing and substantially parallel to said chain, and cam means disposed in said path and in advance of said reach and cooperating with the projection on said first jaw element for tumbling said jaw elements and resetting the same for subsequent movement along said reach with said jaw elements closed and the bite thereof disposed at right angles to said chain.

17. A sheet gripping and conveying device as defined in claim 16, wherein the cooperating cam and spring means for positioning the bite of the jaw elements of the gripper substantially parallel to the chain reach comprises a bar extending along and inclined with respect to said reach, and a spring-pressed toggle member operably connected with the first jaw element for yieldingly urging the same towards said bar.

18. A sheet gripping and conveying device as defined in claim 17, comprising means for pivotally mounting said bar, and means for adjusting said bar about its pivot to vary the inclination thereof.

19. Sheet feeding apparatus for feeding sheets one after another from the top of a stationary upright pile thereof, comprising sheet separating means arranged for vertical up and down movement and operable upon the top of said pile for separating the sheets successively from said pile, sheet conveying means arranged adjacent said pile and extending from substantially the lowermost sheet of said pile upwardly to a level above the top of said piie for removing in succession from said pile in an upward direction the sheets successively separated by said sheet separating means, said conveying means advancing the sheets a predetermined distance for each cycle of operation of the feeder, mechanism for lowering said sheet separating means relative to said pile and said sheet conveying means as the sheets are removed from said pile and the latter is consumed to maintain said sheet separating means in proper operating position in relation to the height of the diminishing pile, and actuating means for operating said sheet separating means at timed intervals in timed relation with the cycle of movement of said conveying means and for advancing the timing of said sheet separating means relative to the cyclic movement of said conveying means a degree commensurate with the extent of downward movement of said sheet separating means by said mechanism, whereby said timing relationship between said sheet separating means and said conveying means is maintained as said sheet separating means descends relative to said pile and said conveying means.

20. Sheet feeding apparatus as defined in claim 19, comprising control means including a feeler element operatively connected with said actuating means for rocking movement in timed relation with said sheet separating means and said sheet conveying means across one edge of the pile into and out of engagement with 21 marginal portion thereof for controlling the operation of said mechanism.

21. Sheet-feeding apparatus as defined in claim 19, wherein the sheet conveying means comprises vertically positioned endless means arranged with a reach thereof adjacent the pile and with the lower turn at a level below the lowermost sheet of said pile and with the upper turn at a level above the top of said pile, and means for driv ing said endless means so that said reach travels in an upward direction.

22. Sheet feeding apparatus for feeding sheets one after another from the top of a stationary upright pile thereof, comprising a sheet separating mechanism arranged for vertical up and down movement and including means operable toward and away from the top of said pile for engaging and lifting an edge portion of each sheet in. turn from said pile, an endless sheet conveyor having an upwardly travelling reach arranged a jacent said pile and extending from substantially the lowermost sheet of said pile to a level above the top of said pile, said con-- veyor carrying sheet grippers at spaced intervals therealong and operable successively to grip the lifted edge portions of successive sheets and remove said sheets from said pile in an upward direction as said grippers travel along said reach, means for lowering said sheet separat ing mechanism relative to said pile and said conveyor 

